1. Field of the Invention
The present invention relates to a semiconductor light emitting apparatus having a semiconductor light emitting element such as semiconductor laser, light emitting diode or the like, and a method of fabricating the same, aiming to prevent destruction, such as electrostatic destruction, of the semiconductor light emitting element, and to make a great stride of improvement in the strength against electrostatic destruction.
2. Description of Related Art
Electrostatic destruction, or electrostatic allowance, is an essential issue of semiconductor light emitting apparatus typically having semiconductor laser element. The electrostatic destruction is categorized into that ascribable to short-circuiting of the semiconductor laser per se, and that ascribable to destruction of light emission end face due to instantaneous increase in the emission intensity. Generally speaking, efforts of improving performances of the laser, such as for lower power consumption and higher efficiency, tend to degrade the electrostatic allowance. This is supposed that decrease in the threshold carrier density Jth and improvement in the differential quantum efficiency possibly worsen damage on the semiconductor laser even under an equivalent level of static electricity. The above-described end face destruction can be solved by adopting so-called window structure which can moderate concentration of light in the end face structure, wherein general methods adopted for the purpose of avoiding the electrostatic destruction including this sort of destruction and of raising the electrostatic allowance, include use of protection elements such as capacitor, diode, thyristor and so forth, which are externally attached. This, however, results in increase in the cost due to increase in the number of process steps or components for the assembly, and increase in the size.
On the other hand, a proposal has been made on a configuration in which a thyristor composing a protection circuit is fabricated into a substrate composing a semiconductor light emitting element (see, for example, Japanese Patent Application Publication No. HEI5-67849, FIG. 1). However, thus-configured semiconductor light emitting apparatus suffers from a complicated configuration such as having a large number of stacked semiconductor layers, and has only a small degree of freedom on selection of characteristics of the thyristor, because voltage and other characteristics of the thyristor can affect characteristics of the semiconductor light emitting apparatus.
However, for an exemplary case where an active layer of a semiconductor light emitting adopts a multiple quantum well structure, characteristics of the apparatus will vary, which is typified by increase in the ON voltage as compared with that in a single-layer structure, so that it will be necessary to correspondently alter a design value of the ON voltage Von of the thyristor.